JP3836060B2 - Radiation generation apparatus and radiation irradiation direction calibration apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiation generation apparatus including a sighting device that positions a radiation irradiation field on a radiation irradiation target, and a radiation irradiation direction calibration apparatus that configures a radiation irradiation direction and a sighting device.
[0002]
[Prior art]
For example, radiation such as X-rays cannot visually confirm the irradiation field. Therefore, a radiotherapy device or an X-ray imaging device used in the medical field irradiates light from illumination through a collimator that regulates the irradiation range in order to visually confirm the irradiation field before irradiation. And the irradiation field is visualized. The shape of the radiation field can be confirmed with a film or a radiation detector. The center of the radiation field is determined based on the distribution of the dose in the radiation field range using the measurement results of the film or radiation detector. Then, the center of the radiation field is projected as a sight with a piano wire or a filter within the range of the light field by illumination. The alignment between the center of the radiation field and the aim by illumination is performed by visual inspection. For example, when a film is used, radiation is irradiated while aiming at a mark provided on the film, and calibration is performed based on the irradiation field projected on the film and the position of the mark.
[0003]
In particular, the radiotherapy apparatus is required to accurately reproduce the irradiation of radiation based on a well-established radiotherapy plan. Therefore, calibration of the center of the irradiation field of the radiation emitted from the radiation generator and the position of the aim by illumination is performed periodically. Moreover, it is confirmed that the center of the radiation field passes through the isocenter in the radiotherapy apparatus that irradiates radiation from multiple directions around the isocenter.
[0004]
[Problems to be solved by the invention]
However, the irradiation field of the light projected by the illumination only projects the irradiation range with a collimator for regulating radiation. Therefore, the outline of the irradiation field becomes unclear due to the diffraction of light.
[0005]
Further, when an aim is made by putting a piano wire or a filter in the middle of the optical path, the aim is greatly enlarged and projected along with the expansion of the irradiation field. Then, diffraction occurs as in the outline of the light irradiation field, and the aim is unclear. Therefore, the line forming the aim cannot be reduced to a certain extent.
[0006]
Further, the alignment of the radiation field and the light field is performed by visual observation. Since radiation is diffracted in the same manner as light, the outline of the radiation field projected on the film is unclear. Accordingly, positioning is difficult with an enlarged aim or an irradiation field with an unclear outline, which limits accuracy.
[0007]
Accordingly, an object of the present invention is to provide a radiation generation apparatus and a radiation irradiation direction calibration apparatus that can easily match a radiation field to an irradiation target.
[0008]
[Means for Solving the Problems]
Therefore, the radiation generating device according to the present invention, or irradiation direction correction means, Ru FIG resolve problems drives out following means.
[0009]
A radiation generator according to the present invention includes a radiation source that emits radiation, a laser oscillator that emits a laser beam, an optical axis adjusting unit that coaxially aligns the axis of the radiation and the optical axis of the laser beam, and a radiation irradiation field. a detector for detecting a detector and replaced with the laser intensity analyzer that will be placed on the axis of the radiation, a camera is positioned relative the source of radiation to observe the irradiation field of the radiation, and acquired by the camera An analysis device that associates information, radiation information detected by the detector with laser beam information detected by the laser intensity analyzer, and a monitor that displays information output by the analysis device.
[0010]
Alternatively, the radiation generating apparatus according to the present invention includes a radiation source that emits radiation, a laser oscillator that emits a laser beam, an optical axis adjustment unit that coaxially aligns the axis of the radiation and the optical axis of the laser beam, and radiation A detector that detects the irradiation field, a beam splitter with a reflection surface that allows the image of the detection surface of the detector viewed from the axis of the radiation to be observed from a position other than the axis, and a detection that is reflected on the reflection surface A camera that observes the image of the surface, a laser intensity analyzer that detects the laser beam reflected by the reflecting surface on the opposite side of the camera from the opposite side of the beam splitter, and the information and detector acquired by the camera. An analysis device that associates the detected radiation information with the laser beam information detected by the laser intensity analyzer, and a monitor that displays information output by the analysis device.
[0011]
In order to position the aim of the laser beam at the center of the radiation field, the radiation irradiation direction calibration apparatus according to the present invention includes a detector that detects the radiation emitted from the radiation source, and is emitted coaxially with the radiation. A laser intensity analyzer that detects and replaces the detected laser beam with a detector, a camera that is positioned relative to the radiation source and observes the radiation field, and the information acquired by the camera and the radiation detected by the detector. An analyzer that associates the information with the information of the laser beam detected by the laser intensity analyzer, and a monitor that displays information output by the analyzer.
[0012]
Alternatively, the radiation generator according to the present invention includes a laser oscillator that emits a laser beam, a detector that detects radiation emitted from the radiation source, and an optical axis that coaxially aligns the axis of the radiation and the optical axis of the laser beam. Adjustment means, a laser intensity analyzer that replaces the detector to detect the laser beam, a camera that is positioned relative to the radiation source and observes the radiation field, and information acquired by the camera and detection by the detector And an analyzer for associating the information on the emitted radiation with the information on the laser beam detected by the laser intensity analyzer, and a monitor for displaying information output from the analyzer.
[0013]
Alternatively, the radiation irradiation direction calibration apparatus according to the present invention includes a detector that detects an irradiation field of radiation emitted from a radiation source and a laser beam emitted within the range of the irradiation field of radiation at the center of the detector. Based on the laser intensity analyzer detected through the provided opening, the information on the radiation detected by the detector and the information on the laser beam detected by the laser intensity analyzer, the center of the radiation field and the laser beam And an analysis device for calculating a positional relationship with the center of the.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The radiation generator 1 which concerns on the 1st Embodiment of this invention is demonstrated with reference to FIG.1 and FIG.2. A radiation generator 1 shown in FIG. 1 includes a radiation source 2, a laser oscillator 3, bend mirrors 4 and 4 a, and a radiation irradiation direction calibration device 10. The radiation irradiation direction calibration device 10 includes a radiation detector 5, a laser intensity analyzer 6, a camera 7, an analysis device 8, and a monitor 9.
[0015]
The radiation source 2 emits X-rays R that are an example of radiation. The laser oscillator 3 emits a laser beam L. As the laser beam L, it is preferable to use a laser in the visible region, specifically, a He—Ne laser, an Ar ion laser, a semiconductor laser or the like that is inexpensive and easy to handle.
[0016]
The bend mirror 4 is an example of an optical axis adjusting unit, and is disposed on the axis A in the emission direction of the X-ray R and reflects the laser beam L in the same direction as the X-ray R. The bend mirror 4 may be arranged on the axis A when irradiating the laser beam L, or may be always arranged on the axis A as long as the X-ray R is sufficiently transmitted. Good. In the present embodiment, another bend mirror 4 a is arranged between the laser oscillator 3 and the bend mirror 4 in order to arrange the laser oscillator 3 in parallel with the radiation source 2. In this way, the optical axis B of the laser beam L can be adjusted to coincide with the axis A of the X-ray R by simply changing the direction of the bend mirrors 4 and 4a without moving the laser oscillator 3. it can. At this time, in each of the bend mirrors 4 and 4a, the optical axis of the laser beam L is not necessarily reflected at a right angle.
[0017]
The radiation detector 5 detects X-rays R emitted from the radiation source 2. The radiation detector 5 includes, for example, a ceramic scintillator, a semiconductor sensor, and the like, and is provided so as to detect the shape of the irradiation field of X-ray R and the distribution of dose. The laser intensity analyzer 6 detects the laser beam L emitted from the laser oscillator 3. The laser intensity analyzer 6 includes a photodiode and detects the luminance distribution of the laser beam L. Either one of the radiation detector 5 and the laser intensity analyzer 6 is disposed on the axis A of the X-ray R and is provided so that it can be replaced with each other. The camera 7 is positioned relative to the radiation source 2 and reflects the detection surface 5 a of the radiation detector 5 or the detection surface 6 a of the laser intensity analyzer 6 installed on the axis A of the X-ray R.
[0018]
The analysis device 8 calculates the center of the X-ray R irradiation field based on the X-ray R information detected by the radiation detector 5, and uses the information on the laser beam L detected by the laser intensity analyzer 6. Then, the center of the laser beam L is calculated. As an example of how to determine the center, there is a method in which the detected peaks of the X-ray R and the laser beam L are respectively centered. The analysis device 8 is based on information obtained by copying the radiation detector 5 with the camera 7 when the X-ray R is detected and information obtained by copying the laser intensity analyzer 6 with the camera 7 when the laser beam L is detected. The positional relationship between the center of the X-ray R irradiation field and the center of the laser beam L is obtained. Then, the analysis device 8 outputs this positional relationship information to the monitor 9. In this case, if so-called superimpose display is performed in which images acquired by the camera 7 are superimposed, it is easy to visually understand.
[0019]
Next, a method for combining the axis A of the X-ray R and the optical axis B of the laser beam L of the radiation generator 1 using the radiation irradiation direction calibration apparatus 10 will be described. In FIG. 2, the radiation detector 5, the laser intensity analyzer 6, the camera 7, the analysis device 8, and the monitor 9 are omitted.
[0020]
As shown in FIG. 2, the radiation field of the X-ray R and the laser beam L are detected at least at two points, in this embodiment, at three points in the direction away from the radiation source 2 along the axis A of the X-ray R. Detector 5 and laser intensity analyzer 6 are used for detection, and the center of each is calculated by analyzer 8.
[0021]
A near point P ₁ , an intermediate point P ₂ , and a far point P ₃ are sequentially set from the side closer to the radiation source 2. The centers of the X-ray R and the laser beam L at each point are A ₁ , A ₂ , A ₃ , B ₁ , B ₂ , B ₃ , respectively. It is conceivable that the axis A and the optical axis B are in a three-dimensional intersection but not in contact.
[0022]
Therefore, first, the deviation of the center _{B 1} of the center _{A 1} and the laser beam L in the X-ray R in the near point _{P 1} is measured and corrected. Deviation appearing in near point _{P 1} is adjusted by the bend mirror 4a. By making A ₁ and B ₁ coincide at the near point P ₁ , the axis A and the optical axis B intersect. Next, to measure the center _A 2 of X-ray R at the midpoint _{P 2} and the far point _{P 3, A 3} and the laser beam L center _B 2, _{B 3} of deviation, respectively. The deviation between A ₂ and B ₂ and A ₃ and B ₃ is proportional to the distance from the near point P ₁ to the intermediate point P ₂ and the distance from the near point P ₁ to the far point P ₃ . That is, a deviation proportional to the distance from the near point P ₁ to the bend mirror 4 should similarly occur in a plane parallel to the near point P ₁ through the point where the bend mirror 4 and the axis A intersect.
[0023]
Therefore, next, the deviation between the axis A and the optical axis B in the bend mirror 4 is corrected based on the ratio of the deviations A ₂ and B ₂ and A ₃ and B _{3 at} the intermediate point P ₂ and the far point P ₃ . At the near point P ₁ , the centers A ₁ and B ₁ are shifted again, but the deviations of A ₁ and B ₁ , A ₂ and B ₂ , and A ₃ and B ₃ are proportional to the distance from the bend mirror 4 to each point. It should be.
[0024]
Therefore, the misalignment at the near point P ₁ , the intermediate point P ₂ , and the far point P ₃ is confirmed again, and the bend mirror 4 is adjusted based on this, whereby the X-ray R axis line A and the laser beam L light. Axis B can be matched.
[0025]
Note that the adjustment method described above is an example, and other methods may be used. Far point P _3, when set farther than the irradiation distance X ray R in the case of using a radiation generating apparatus 1, it is possible to reduce the error.
[0026]
The radiation generator 1 configured as described above uses the laser beam L because the optical axis B of the laser beam L is arranged coaxially with the axis A of the X-ray R by the radiation irradiation direction calibration device 10. The X-ray R irradiation field can be easily positioned on the irradiation target. Further, the center of the irradiation field of the X-ray R and the center of the laser beam L are calculated by the analysis device 8 based on information detected by the radiation detector 5 and the laser intensity analyzer 6, respectively. Therefore, the center of the X-ray R and the center of the laser beam L can be accurately aligned, and the reproducibility is excellent.
[0027]
Further, when the radiation generating apparatus 1 is mounted on a radiotherapy apparatus, it can be positioned using a laser beam, so that it is possible to accurately irradiate the affected area to be irradiated with X-rays.
[0028]
In the present embodiment, the radiation irradiation direction calibration device 10 is used when the axis A of the X-ray R and the optical axis B of the laser beam L are matched, and is not always used. Therefore, you may provide so that it can remove from the radiation generator 1. FIG. In this case, the radiation irradiation direction calibration apparatus 10 applies a radiation axis and an optical axis of the laser beam to the radiation generation apparatus 11 including the radiation source 2, the laser oscillator 3, and the bend mirrors 4 and 4a as necessary. And adjust.
[0029]
A radiation generator 21 according to a second embodiment of the present invention will be described with reference to FIG. In addition, about the same structure as the radiation generator 1 of 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
[0030]
In the radiation generating apparatus 21 shown in FIG. 3, the prism 22 is used as the optical axis adjusting means, and the beam splitter 23 is disposed between the prism 22 and the radiation detector 5 as compared with the first embodiment. Different. The beam splitter 23 has a reflection surface 23a that reflects an image obtained by viewing the detection surface 5a of the radiation detector 5 from the axis A of the X-ray R. Therefore, the camera 7 is arranged so as to observe the image of the detection surface 5a reflected on the reflection surface.
[0031]
Further, a part of the laser beam L emitted coaxially with the X-ray R is reflected on the side opposite to the camera 7 by the reflecting surface 23a. Therefore, the laser intensity analyzer 6 is arranged so as to detect the laser beam L reflected by the reflecting surface 23a. The laser intensity analyzer 6, the camera 7, and the beam splitter 23 are aligned on a straight line.
[0032]
In the radiation generator 21, the radiation detector 5, the laser intensity analyzer 6, the camera 7, the analyzer 8, the monitor 9, and the beam splitter 23 constitute a radiation irradiation direction calibration device 24, which comprises a radiation source and a laser. The present invention may be applied to the adjustment of the radiation axis and the optical axis of the laser beam, such as a radiation generating apparatus including an oscillator and an optical axis adjusting unit, for example, 11 in FIG. 1 and 25 in FIG.
[0033]
As described above, by arranging the beam splitter between the prism 22 and the radiation detector 5, the X-ray R and the laser beam emitted coaxially without replacing the radiation detector 5 and the laser intensity analyzer 6 can be used. L can be detected simultaneously. Further, it does not take time to replace the radiation detector 5 and the laser intensity analyzer 6, and it is not necessary to check and correct misalignment caused by the replacement.
[0034]
A third embodiment of the present invention will be described with reference to FIG. In addition, about the same structure as the structure demonstrated in 1st and 2nd embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 4, in the third embodiment, the radiation generation device 31 includes a radiation source 2, a laser oscillator 3, and bend mirrors 4 and 4 a, and the radiation irradiation direction calibration device 32 includes a radiation detector 35. And a laser intensity analyzer 6, an analysis device 8, and a monitor 9.
[0035]
The radiation detector 35 includes four detection units 35a. Each detector 35a is arranged in two columns and two rows with a gap through which the laser beam L can pass. As a result, a gap intersection C is formed at the center of the radiation detector 35 as an opening through which the laser beam L passes. At the intersection C, the laser intensity analyzer 6 is disposed on the opposite side of the detection surface 35b for detecting the X-ray R.
[0036]
As shown in FIG. 5A, the analysis device 8 uses the information of the X-rays R detected by the radiation detector 35, and the corners of the respective detection units 35a arranged at diagonal positions at the intersection C. obtaining an intersection S ₁ of a line connecting the. Similarly, as shown in FIG. 5 (B), the analysis device 8 is arranged at each diagonal position at the intersection C based on the information of the laser beam L detected by the laser intensity analyzer 6. obtaining an intersection S ₂ of the line connecting the corners of the shadow projected by the detecting section 35a. Since the obtained intersection point S ₁ and intersection point S ₂ are caused by the angle of the detection unit 35, the intersection point of the irradiation field of the X-ray R and the center of the laser beam L may be used as a reference point. it can. Therefore, the camera 7 may not be provided, but can be used as a guide for adjusting the optical axis, particularly when the center of the laser beam L is significantly deviated from the intersection C.
[0037]
The analysis device 8 obtains the center of the X-ray R irradiation field from the X-ray R dose distribution detected by the radiation detector 35 and the energy distribution of the laser beam L detected by the laser intensity analyzer 6. From this, the center of the laser beam L is obtained. Since the centers are associated with each other by the reference point, it is possible to obtain a positional deviation from each other.
[0038]
As described above, the radiation irradiation direction calibration device 32 can align the X-ray R axis A of the radiation generator 31 and the optical axis B of the laser beam L coaxially with high accuracy. In addition, since the radiation generator 31 includes the laser oscillator 3 that emits the laser beam L as a sight indicating the center of the irradiation field of the X-ray R, the X-ray R axis A and the laser beam L are emitted by the radiation irradiation direction calibration device 32. The optical axis B can be aligned coaxially with high accuracy. Therefore, the radiation generator 31 can improve the positioning accuracy of the irradiation direction of the X-ray R with respect to the irradiation target.
[0039]
If the radiation generator of each embodiment is applied to a radiation therapy apparatus or the like, and a laser beam aiming is used to correct the mechanical operation of the radiation therapy apparatus, the laser beam is analyzed by laser intensity analysis. Any wavelength can be used as long as it can be detected by the instrument. Therefore, in this case, the laser oscillator is not limited to one that emits a laser beam in the visible region.
[0040]
【The invention's effect】
The radiation generator according to the present invention includes a laser oscillator in which the emitted laser beam is coaxially aligned with the axis of the radiation as an sighting device. Therefore, the radiation field can be easily positioned toward the radiation target. Moreover, the optical axis of the laser beam can be accurately aligned with the axis of the radiation by the radiation irradiation direction calibration device including the radiation detector, the laser intensity analyzer, the camera, the analysis device, and the monitor.
[0041]
Further, according to the radiation irradiation direction calibration apparatus according to the present invention, the analysis apparatus associates the position of the radiation detector that detects the radiation with the position of the laser intensity analyzer that detects the laser beam, and the center of the radiation irradiation field. Since the positional relationship between the laser beam and the center of the laser beam is obtained, the axis of the radiation emitted from the radiation generator equipped with the laser oscillator can be aligned with the optical axis of the laser beam with high accuracy.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a radiation generating apparatus according to a first embodiment of the present invention.
2 is a perspective view showing the positional relationship between the radiation axis of the radiation generator of FIG. 1 and the optical axis of a laser beam.
FIG. 3 is a perspective view showing a radiation generating apparatus according to a second embodiment of the present invention.
FIG. 4 is a perspective view showing a radiation generation apparatus and a radiation irradiation direction calibration apparatus according to a third embodiment of the present invention.
5A is a view showing information of X-rays detected by the radiation detector of FIG. 4; FIG.
(B) is a figure which shows the information of the laser beam detected by the laser intensity analyzer of FIG.
[Explanation of symbols]
1, 21, 31 ... Radiation generator 2 ... Radiation source 3 ... Laser oscillator 4, 4a ... Bend mirror (optical axis adjusting means)
DESCRIPTION OF SYMBOLS 5 ... Radiation detector 5 ... Detection surface 6 ... Laser intensity analyzer 7 ... Camera 8 ... Analysis apparatus 9 ... Monitor 10, 24, 32 ... Radiation irradiation direction calibration apparatus 22 ... Prism (optical axis adjustment means)
23 ... Beam splitter 23a ... Reflecting surface A ... Axis line B ... Optical axis R ... X-ray (radiation)
L ... Laser beam

Claims (5)

A radiation source for emitting radiological,
A laser oscillator that emits a laser beam;
An optical axis adjusting means for coaxially aligning the axis of the radiation and the optical axis of the laser beam;
A detector for detecting the radiation field;
A laser intensity analyzer replaced with the detector and placed on the axis of the radiation;
A camera that is positioned relative to the radiation source to observe the radiation field;
An analyzer for associating information acquired by the camera, information of the radiation detected by the detector, and information of the laser beam detected by the laser intensity analyzer;
A radiation generation apparatus comprising: a monitor that displays information output by the analysis apparatus. A radiation source that emits radiation; and
A laser oscillator that emits a laser beam;
An optical axis adjusting means for coaxially aligning the axis of the radiation and the optical axis of the laser beam;
A detector for detecting the radiation field;
A beam splitter provided with a reflecting surface for observing an image of a detection surface of the detector as viewed from the axis of the radiation from a position other than the axis;
A camera for observing an image of the detection surface projected on the reflection surface;
A laser intensity analyzer for detecting the laser beam reflected by the reflecting surface on the opposite side of the camera with respect to the beam splitter on the opposite side of the camera;
An analyzer for associating information acquired by the camera, information of the radiation detected by the detector, and information of the laser beam detected by the laser intensity analyzer;
A radiation generation apparatus comprising a monitor for displaying information output by the analysis apparatus. A detector for detecting radiation emitted from the radiation source;
A laser intensity analyzer for detecting a laser beam emitted coaxially with the radiation by replacing the detector;
A camera that is positioned relative to the radiation source to observe the radiation field;
An analyzer for associating information acquired by the camera, information of the radiation detected by the detector, and information of the laser beam detected by the laser intensity analyzer;
A radiation irradiation direction calibration apparatus comprising: a monitor that displays information output by the analysis apparatus. A laser oscillator that emits a laser beam;
A detector for detecting radiation emitted from the radiation source;
An optical axis adjusting means for coaxially aligning the axis of the radiation and the optical axis of the laser beam;
A laser intensity analyzer that is replaced with the detector to detect the laser beam;
A camera that is positioned relative to the radiation source to observe the radiation field;
An analyzer for associating information acquired by the camera, information of the radiation detected by the detector, and information of the laser beam detected by the laser intensity analyzer;
A radiation generation apparatus comprising: a monitor that displays information output by the analysis apparatus. A detector for detecting an irradiation field of radiation emitted from the radiation source;
A laser intensity analyzer that detects a laser beam emitted within the range of the radiation field through an opening provided in a central portion of the detector;
Based on the information on the radiation detected by the detector and the information on the laser beam detected by the laser intensity analyzer, the positional relationship between the center of the radiation field and the center of the laser beam is calculated. And a radiation irradiation direction calibration apparatus, comprising:

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